On Mechanical and Electrical Coupling Determination at Piezoelectric Harvester by Customized Algorithm Modeling and Measurable Properties

Abstract

Piezoelectric harvesters use the actuation potential of the piezoelectric material to transform mechanical and vibrational energies into electrical power, scavenging energy from their environment. Few research has been focused on the development and understanding of the piezoelectric harvesters from the material themselves and the real piezoelectric and mechanical properties of the harvester. In the present work, the authors propose a behavior real model based on the experimentally measured electromechanical parameters of a homemade PZT bimorph harvester with the aim to predict its Vrms output. To adjust the harvester behavior, an iterative customized algorithm has been developed in order to adapt the electromechanical coupling coefficient, finding the relationship between the harvester actuator and generator behavior. It has been demonstrated that the harvester adapts its elongation and its piezoelectric coefficients combining the effect of the applied mechanical strain and the electrical behavior as a more realistic behavior due to the electromechanical nature of the material. The complex rms voltage output of the homemade bimorph harvester in the frequency domain has been successfully reproduced by the proposed model. The Behavior Real Model, BRM, developed could become a powerful tool for the design and manufacturing of a piezoelectric harvester based on its customized dimensions, configuration, and the piezoelectric properties of the smart materials.

Electrical Response Analysis of a Piezoelectric Energy Harvester Power Source Based on Electromechanical Parameters

“…Electronics 2022, 11, x FOR PEER REVIEW 3 of 12 was developed by [27], taking into account the experimental data obtained for a bimorph piezoelectric harvester, as a consequence, the results are closer to real piezoelectric power source behavior. Figure 1 represents the piezoelectric generator equivalent circuit with all the electromechanical parameters used in the simulation process named.…”

“…The mechanical parameters related to the piezoelectric material that govern its electrical behavior have been modeled like the components of an electrical circuit following the Butterworth van Dyke model [26]. Based on that configuration, the piezoelectric model used to analyze the harvester's electrical response was developed by [27], taking into account the experimental data obtained for a bimorph piezoelectric harvester, as a consequence, the results are closer to real piezoelectric power source behavior.…”

“…The hypothesis that relates the inertia of a solid body with inductance in the electrical model is a bit more complex than the previous two. As defined by [27], this hypothesis is based firstly on the proportion between the electrical potential of a piezoelectric harvester and the applied force, and secondly on the capacity of the dipole charge generation as a consequence of the resulting speed of the harvester due to the vibration conditions. Finally, these two phenomena determine the amount of electrical current generated, as well as the inductance, in the electrical circuit.…”

“…In circuit analysis, this transformation ratio is not common. The relation that the transformer represents is defined by [27] as the voltage in mesh 1 with the integral of the current in mesh 2.…”